My XLi has an X72 rubidium reference but the pinout should be the same, it looks like a common interface board is used regardless of the oscillator type. The J13 pinout, with Pin 1 being on the lower right and Pin 10 being upper left, is: Pins 1,2 are +12V Pins 3,4 are GND Pins 5,6 are -12V Pins 7,8 are used to indicate which oscillator is installed Pin 9 is the DAC output to the reference Pin 10 is the lock detection input, driven from the reference (at least for Rb) Pin 7 shorted to ground with Pin 8 open indicates an OCXO Pin 7 open with Pin 8 shorted to ground indicates a High Stability OCXO Pins 7 and 8 shorted to ground indicate a Rubidium oscillator William > Date: Fri, 2 Jun 2023 23:10:15 +0200 > From: comsec22 <comsec22@gmail.com> > Subject: [time-nuts] Symmetricom XLi > To: Discussion of precise time and frequency measurement > <time-nuts@lists.febo.com> > Message-ID: > <CANbURZ_fU7DC-iq4tkhLXQbLitL3QwZw8ZPtgQYnNZsu7tMz= > A@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > I am looking for a way to add the OCXO inside the receiver. > There is a coax P2 on the daughter board for the 10 Mhz in plus J13 (5 +5 > pin). > I guess P13 is feeding + 5 V, +12 V and - 12 V. > A VCO signal to control the OCXO should be there too.. > > Has anyone the same unit, at least to get a picture ? Unfortunately no > drawings on the web. > > Cheers >